Magnetic compasses are subject to magnetic variation and magnetic deviation errors which prevent the direct indication of true compass heading. Magnetic deviation is the difference between true and magnetic north, which difference varies from location to location in accordance with the particular configuration of the earth's magnetic field at a given location. Magnetic variation, which also results in compass error, is caused by local magnetic effects such as masses of magnetizable or magnetic material including the hull of a vessel aboard which a compass is employed. Magnetic variation is conventionally compensated by use of correcting spheres which are magnetizable iron masses positioned with respect to the compass to compensate for the local error. Deviation correction is accomplished by a correction table or chart setting forth the relationship between true and magnetic headings for a specific geographic region.
Remote reading magnetic compasses are known wherein an electrical signal indication is provided which is representative of compass heading. Such remote reading compasses are especially useful since a plurality of displays can be provided remotely from the compass itself for indicating at various positions compass heading via a digital or other suitable display. However, such compasses are subject to the same variation and deviation errors of all magnetic compasses.